This disclosure relates generally to a method and/or architecture for implementing amplifiers and, in particular, to methods and/or architectures for implementing transimpedance amplifiers that yield an improved group delay distortion over a range of frequencies.
A transimpedance amplifier (TIA) converts an input current to an output voltage mainly set by a trans-impedance. The TIA may be implemented using an operational amplifier, or op-amp.
A TIA may be implemented to amplify the current output of a photodiode. The TIA presents a low impedance to the photodiode for higher bandwidth and isolates it from the output voltage of the op-amp. The gain of the TIA may be set by a feedback resistor.
Group delay refers to the time delay of amplitude envelopes of the various sinusoidal components of a signal through a device, as a function of frequency for each component. The signal delay can be different for various frequencies, resulting in distortion of signals with multiple frequency components. Such delay variation and resulting distortion can cause problems such as, for example, poor fidelity or intersymbol interference (ISI) in data transmission.